The operation of a typical case packer may be taken as a starting point for an explanation of the invention. Articles such as glass containers are continuously supplied to the packer by a conveyor. The moving articles are formed into a predetermined number of parallel lines, typically although not necessarily two, three or four lines. The incoming articles are essentially in single file relation in each line. The conveyor feeds the articles into an array-forming section of the packer which is commonly referred to as the "head." There the articles are grouped or segregated into a desired pattern for packing. This array, i.e., the number of lines and the number of articles in each line, corresponds to the particular case into which the articles are to be packed. The most commonly used arrays include 3.times.4 ("12 pack"), 3.times.5, 3.times.6, and 4.times.6, although others are sometimes used. The lines are separated in lanes, spaced apart by lane dividers. The articles are fed into the respective lanes by line pressure, that is, the push which arises from the movement of the articles in the conveyor.
In the lanes the articles rest on a so-called "shiftable grid," which comprises a series of underlying parallel bars which extend longitudinally along the center planes of the respective lanes. A sensing means such as a photocell, senses when all of the lanes have been filled by the incoming articles. It then triggers a grid shift cylinder which shifts the grid transversely, so that the grid bars are moved out from beneath the articles, and the unsupported but still arrayed articles drop from the head, under the influence of gravity.
Where the articles are to be packed in upright position in the case, they drop directly from the head into the case, which is positioned below to receive them. As they drop, the articles are guided toward and into the respective cells, between the partitions of the case, by a so-called "intermediate grid." This grid presents a series of flexible fingers or flaps around the fall path of each bottle, which "funnel" the article into its particular cell. Case packers having such features are shown in the U.S. Pat. Nos. to Raudat 3,561,189; Rowekamp 3,353,331; and Wild 3,479,791, to which reference may be had for further background details.
It is sometimes necessary to pack containers in inverted condition, i.e., neck down in the case. For such invert packing, the packer will include a container-inverting mechanism below the upper head. The inverting mechanism turns the containers upside down after they have been arrayed, and before they are released into the cells of the case. According to one technique for accomplishing such inversion, as shown in U.S. Pat. Nos. 3,694,993 to East, and 3,852,938 to Graff, the arrayed containers are dropped upright from the head onto vacuum cups which engage and grip them at the bottom. The vacuum gripping section, holding the containers, is then inverted 180.degree.. Once inverted, the vacuum is released and the containers drop into the case. Again, they may be guided or funneled as they fall by an intermediate grid. In another type of invert packer, shown in Birrell U.S. Pat. No. 3,443,355, the bottles are gripped at their sides by jaws (rather than by vacuum cups at the bottom), then inverted and dropped into the case.
Any automatic case packer must be matched to the size of the particular articles which it is to pack and to the array which the case accepts. Different arrays as well as different articles sizes may require not only different numbers of lanes, but also different lane widths and lane lengths. The dimensioning must also be reflected in the shifting grid, the inverting mechanism (if used), and the intermediate grid below it.
In the glass container industry, manufacturers typically produce containers in a wide range of sizes. They are packed by the manufacturer in corrugated cases of different sizes and arrays, for shipment to food and beverage processors for filling. There has not heretofore been available suitable structure for accommodating, in a single packer, the many different sizes and arrays of articles which that machine may be used to pack. As an example, a typical glass container manufacturer may produce and pack more than 30 different types of containers having sizes which may range from 13/4inches in diameter up to more than five inches. In order to enable a given machine to handle articles of different sizes, it has been the common practice to use a series of several heads, shifting grids and intermediate grids, each individually sized to handle a different particular size and array of ware to be packed. These parts, which are known collectively as "change parts" because they permit change of size, are adapted to be interchangeably mounted in a given packer, according to the articles to be packed. It will be apparent that a capability for packing a wide range of articles requires a correspondingly large inventory of change parts for adapting the packer to the particular articles.
It has been the objective of this invention to provide "universal" structures for the head and intermediate grid, which will enable a case packer to handle various arrays and a wide range of article sizes, without the multiplicity of change parts heretofore necessary.